Requirements for surface expression and function of adhesin P1 from Streptococcus mutans
Requirements for surface expression and function of adhesin P1 from Streptococcus mutans
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DOI：
10.1128/iai.01315-07
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发表时间：
2008-06-01
影响因子：
3.1
通讯作者：
Brady, L. Jeannine
中科院分区：
文献类型：
--
作者：
Crowley, Paula J.;Seifert, Trevor B.;Brady, L. Jeannine
在这份报告中，我们定义了变形链球菌粘附素P1成功易位和功能成熟的要求。进一步鉴定了由抗P1单抗识别的构象表位，从而便于使用特定的单抗作为工具来监测不同形式的蛋白质的位置。我们表明，P1的正确定位取决于分子本身的结构特征，包括在分泌之前在细胞内发生的必要的A区-P区分子内相互作用。蛋白质折叠-分泌-周转机构中的几个成员也对P1产生影响。在没有触发因子PPIase同系物RopA的情况下，它不能实现完全功能的形式，当DNAK水平受限时，它的易位被延迟。此外，在缺乏富含丙氨酸的P1的情况下，与富含Pro的重复结构域相比，dNAK信息水平发生了差异的变化。最后，在没有htrA的情况下，缺乏P区的非分泌P1在细胞内积累，这意味着细胞内的HtrA蛋白酶功能参与了这种特殊的内部缺失多肽的降解和周转。然而，对全长P1的影响则相反，这表明HtrA的功能和影响存在一种感知机制和底物依赖的变化，这与其已知的在伴侣和蛋白酶之间切换的已知能力一致，这取决于环境扰动。
In this report, we define requirements for the successful translocation and functional maturation of the adhesin P1 of Streptococcus mutans. Conformational epitopes recognized by anti-P1 monoclonal antibodies (MAbs) were further characterized, thus facilitating the use of particular MAbs as tools to monitor the locations of various forms of the protein. We show that correct localization of P1 is dependent on structural features of the molecule itself, including a requisite A region-P region intramolecular interaction that occurs within the cell prior to secretion. P1 also was shown to be affected by several members of the protein-folding-secretion-turnover apparatus. It does not achieve a fully functional form in the absence of the trigger factor PPIase homolog RopA, and its translocation is delayed when DnaK levels are limited. In addition, dnaK message levels are differentially altered in the presence of P1 lacking the alanine-rich compared to the proline-rich repeat domains. Lastly, nonsecreted P1 lacking the P region accumulates within the cell in the absence of htrA, implying an intracellular HtrA protease function in the degradation and turnover of this particular internal-deletion polypeptide. However, the opposite effect is seen for full-length P1, suggesting a sensing mechanism and substrate-dependent alteration in HtrA's function and effect that is consistent with its known ability to switch between chaperone and protease, depending on environmental perturbations.